1. Field of the Invention
The present invention relates to a yaw rate sensor.
2. Description of the Related Art
It is known to mount a yaw rate sensor on a rotatable body in order to measure a yaw rate of a rotary motion of the body. A yaw rate sensor generally has two vibration-capable masses, which may also be referred to as partial vibrators, i.e., a first vibrating mass and a second vibrating mass which may be driven to vibrate in the opposite direction with the aid of a drive. This means that the first vibrating mass and the second vibrating mass vibrate phase-shifted by 180° (antiparallel) with respect to one another. Therefore, the vibrating motions of the first vibrating mass and of the second vibrating mass are also frequently referred to as vibrating motions in phase opposition, or also as an antiparallel mode.
When the body having the yaw rate sensor mounted thereon undergoes a rotary motion about a rotational axis which is not parallel to the vibration direction of the vibrating masses, and at the same time the two vibrating masses are excited to undergo their antiparallel vibrating motions, Coriolis forces act on the two vibrating masses. As a result of the Coriolis forces, the two vibrating masses are each deflected perpendicularly to their vibration direction. The two vibrating masses are deflected in opposite directions due to the antiparallelism of the vibrating motions of the two vibrating masses. Such an opposed vibration direction may also be referred to as an antiparallel detection vibration. This antiparallel detection vibration may be capacitively detected and converted into a yaw rate with the aid of an evaluation electronics system. The deflection of a vibrating mass is proportional to the Coriolis force acting on the vibrating mass. Thus, the deflection of the vibrating mass corresponds to the yaw rate of the rotary motion of the body.
Such a yaw rate sensor is known from published German patent application document DE 10 2008 042 369 A1, for example.
In addition to their two use modes, i.e., the drive mode and the detection mode, such yaw rate sensors in the related art may have additional vibration modes, so-called spurious modes. These spurious modes are superimposed during operation of the yaw rate sensor, and may result in false signals.